Alternating-current generator



Feb. 24. 1925. 1,527,553

l.. F. HOWARD ALTERNATING CURRENT GENERATOR Filed Feb. 28, 1923 AINVENTOR BY f1,- mm

# ATTORNEY Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

LEMUEL F. HOWARD, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, 0F SWISSVALE, PENNSYLVANIA, A COR- PORATION OF PENNSYLVANIA.

ALTERNA'IING-CURRENT GEN ERAT O R.

Application filed February 28, 1923. Serial No. 621,922.

T 0 all 107mm t mary concern:

Be it known that I, LEMUEL F. HOWARD, a citizen of the United States,'residing at Edgewood Borough, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Alternating-Current Generators, of which the following is a specification.

My invention relates to alternating current generators and particularly to generators of the inductor type. Generators constructed in accordance with my invention are particularly adapted for, though in no way limited to, mounting on axles of railway vehicles.

I will describe one form of alternating current generator embodying my invention, and will then ypoint out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a view, partly diagrammatic, showing, in front elevation, one form of alternating current generator embodying my invention. Fig. 2 is an end view of the generator shown in Fig. l.

Fig. 3 is a perspective view showing the manner in which the exciting and generating coils are arranged. y v

Referring to the drawings, the reference character A designates a rotatable shaft as the axle of a locomotive or other railway vehicle. Supported on this axle and arranged to rotate therewith is a paramagnetic rotor C which is preferably made in two parts which are fastened in place on the axle by means of bolts C as best shown in Fig. 2. One advantage of this method of construction is that the rotor may be mounted upon the axle without removing the wheels. This rotor comprises a flat plate of elliptical shape which is provided at its extremities with two outstanding projections NA so disposed that their axes and the center of the axle A all lie in the same plane. Spaced from this rotor and also fastened to axle A is another rotory B, similar lin all respects to rotor C. The two rotors are so disposed that the outstanding projections N on rotor B are opposite the similar projections on rotor C and that these projections face each other.

Interposed between these two rotors is a paramagnetic stator D which is supported on the frame of the vehicle by means not essential to my present invention and omitted from the drawings for the sake of simplicity. The stator is provided with a central aperture F which receives the axle A with considerable clearance. This stator may be made in two parts in the same manner as the rotors B and C to facilitate mounting it in place, the two parts being united by belts 10. The stator comprises a fiat body having a pair of outstanding poles I and E which are oppositely disposed, and a similar pair of poles J and K also oppositely disposed. These poles are so located that when pole I is opposite one projection N on rotor B, the pole J is opposite the other projection N of the same rotor. At the same time poles E and K are oppo site the projections N of rotor C.

As shown in Fig. 2 the stator body is provided on its two sides with two windings L and M respectively. These windings are supplied with direct current from some convenient source as a battery R, and are wound in such directions that if the magnetic flux in the left hand side of the stator is directed upwardly, the flux in the right hand side is also directed upwardly. When the parts are in the positions shown in the drawing, the iux so generated passes up both sides of the stator body and at the top divides, part passing through pole E, rotor C, and pole K, baclr into the stator body, and part through pole I, rotor B and pole J back to the stator bodv. Since the stator body is rigidly attached to the frame of the vehicle and the rotors are rigidly attached to the axle, these members will suffer relative displacement as the axle rotates during motion of the vehicle. When the rotors are in the positions shown in the drawing, the rotor bodies and the projections thereon are parts of the magnetic circuits and considerably reduce the reluctance of these circuits. Then the rotors are at 90 angular degrees from these positions, the linx must pass through a large air gap on each side of the stator and the reluctance of the magnetic circuits is considerably higher. Hence as the projections of the rotor elements move successively into and out of alignment with the poles of the stator the flux in the stator body and poles is successively increased and diminished. I propose to utilize this phenomenon for generating alternating current by providingthe poles E, I, J and K with windings l, 2, 3 and e, respectively, which windings vare connected in Vseries i and oare woundv in suchV directions that the voltages induced in the four windings at a given instant are additive. These windings I shall collectively term the alternating cur- .-iluX diminishes at an increasing rate, thus inducing an increasingvoltage of a `given polarity in the alternating current coil. Vhen the rotor projections have 'moved 90 angular degrees from the stator poles,the value of the -lux is 1a minimum but the rate of change of flux iszero, therefore this rate must have reached admaxiinum and decreased. The increase, ,maximum and decrease inthe rate of change oi 'flux corresponds to the alternating induced electromotive force whichv also. grows toca `maximum anddecreases to zero. Nowas the rotors continue to move in the samedirection, the iiux begins to increase again and the increasing rate of change causes an `increasing induced voltage which reaches a maximumandfagain decreases tol-Zero but in this case the voltagefis inthe opposite direction since it isinduced-by an increasing flux instead `of a decreasing `i'luX. T-vVhen the rotors have moved through 180 vangular degrees they again bringtlieir projections into line with the stator polesand the cycle is repeated. It isY therefore clear` that there is generated in the windings 1,2, 3 and 4 an alternating electromotive force whose frequency' is directly proportional to the speed of rotation of the axle A.

Although I have hereinl shown and` described only lone form of `alternating current generator embodying my invention, it is Vunderstood that various changes `.and modifications may be made therein with-in the scope of the 4appended claims without departing from the spirityand scope of my invention.

l Having thus described my invention, what I claim is:

l/In combination, Y a rotatable axle, a stator having an annular ring of parainagnetic material made` in twofseparatefparts' adapted to beclamped around the aXle,vtwo coils wound in opposite directions on opposits sides of said ring, acircuitfor said coils in series including a source of direct current, and means responsive to variations in 'magnetic' y:flux through "said ring -forlprovcircuiti@ said coils'inwseries including a source offdirectcurrent, outstanding; ypoles of paramagnetic material located on said ring midway between said coils, means, for v`80 periodically -moving a paramagnetic. member adj ae'eiitthe"said-poles thereby periodically varyingythe l. magnetic iflux 1 through vsaid poles, and-means responsive to-variations in magnetic flux through said poles for produc- S5 ing an alternating electromotive force.y

liilcombiiiation, a rotatable-axle7 a statonmernber having an annular. ring kof para-magneticmaterial .made ci two parts adapted to be clamped aroundsaid axle, aja- A magnetic circuit includingboth Vsides of `'said Vring, in parallelv an, air.; gap, means for i producing magnetic flux insaidrcircuit, two

outstanding poles on saidring, arotor Velef mentlfmade of two partsradapted to ber95 clamped to said yaxle and having outstanding projections .arranged to periodically come opposite said po-lesfwhereby the reluctance ofsaid circuit is considerably 'decreased and the magnetic flux in said circuit is'cor- .100-

-respondingly.increased, and a winding of wire on'- each said pole so n connected that the voltages induced at `any `instant byv the change .-in, said flux are additive.

i.v Analternating` current generator comrr105 prising-a rotatable axle, a stator having an annular .ring offparamagnetic material con lsisting-...of two parts adapted toi'be clamped together-about saidjaXle,\-two coils wound inoppos'ite fdirections on :opposite sides of, 110

*saidV1 ring, a circuit for said coils in series Vincludingrafsoui'ce oi `direct current, means adapted to.be clamped on saidaXle for periodically varying Vthe flux through said stator, and- Vmeans en -said stator responsive.v 115 tovaria-tions inthe .tluxthrough-the ring for producing air-alternatingelectromotive force. j I

5. -In combination, ia rotatable axle, two

members of -paramagneticmaterial arranged- -to-be clamped together to orm'an annular ring having'a central aperture capable of receiving the axle'with considerable clearance, means for creating a uni-'directional flux throughfsaid-ring, Aa rotor comprising 125 two parts arrangedto be clamped on said axle to ,periodically varythe flux' through the ring, and ymea-ns responsiveto variations in the flux. through saidvringfor creating an alternating electromotive'force. 130

6. In combination, a rotatable axle, a. stator element comprising an annular ring of paramagnetic material adapted to be clamped around said a-Xlel in spaced relation therewith, means for creating a unidirectional magnetic flux in said ring, a rotor element made in two parts adapted to be clamped to said axle and arranged to periodically vary the flux through said ring, and means responsive to variations in the flux through said ring to create an alternating electromotive force.

7. In combination, a rotatable axle, a. stator element comprising an annular ring of paramagnetic material adapted to be clamped around said axle in spaced relati-on therewith, means for creating a undirectional magnetic flux in said ring, a rotor element made in two parts adapted to be clamped to said axle and arranged in inductive relation with said stator element to periodically vary the flux therethrough, and means responsive to Variations in the flux through said ring to create an alternating electromotive force.

In testimony whereof I affix my signature.

LEMUEL F. HOWARD. 

